Switching apparatus



1938- H. F. OBERGFELL SWITCHING-APPARATUS 2 Sheets-Sheet 2 Filed Dec.28, 1937 FI S HERBERT F. OBERGF'ELL INVENT R BYAsmb ATTORNEYS.

Patented Nov. 22, 1938 UNITED STATES PATENT OFFICE SWITCHING APPARATUSApplication December 28, 1937, Serial No. 182,136

4 Claims.

The present invention relates to switching apparatus and moreparticularly to improvements in switching apparatus suitable for use inautomatic telephone exchanges.

As pointed out in the co-pending application, Serial No. 142,966 ofClarence E. Lomax and John H. Voss, filed May 1'7, 1937, one of themajor items of cost, as regards the construction and installation of anyautomatic telephone exchange, is that of constructing the multiplesextending between the bank contacts of the various auto matic switches.In accordance with conventional practice, this construction work isperformed manually,.each multiple conductor being soldered at severalcorresponding contacts, respectively in- 'cluded in the switches of aparticular group. By employing the improved arrangements disclosed inthe above-mentioned co-pending application, the construction andinstallation costs are ma- 2o terlally reduced through the expedient ofusing uninsulated conductors which serve both as multiple conductorsbetween a plurality of switches and as wiper contacts for the wipers ofthe individual switches. In this improved arrangement the lines incomingto each switch are terminated at common bus bar connecting elements withwhich the wipers of the switch are adapted to engage during the rotationthereof into contact with selected sets of the bank conductors. Thisnecessarily means that each conductor connection through the switchinvolves two sets of series connected contact points, thereby increasingthe possibility of trouble due to faulty contact conditions.

It is an object of the present invention to provide improved switchingapparatus of the general form briefly described above, which is ofsimple and economical construction, and wherein series connected sets ofcontacts within the switch structure are entirely eliminated.

The improved apparatus as described in de-- tail hereinafter, isillustrated as including a plurality of substantially parallel spacedbank conductors, all positioned in substantially the same plane andadapted to serve both as multiple conductors and as bank contacts for aplurality of multi-contact relays. To this end, a plurality of wipersarranged in sets with the wipers of each set positioned on a lineextending transversely with respect to the bank conductors, areprovided. Each of the wipers includes a wiper end oppositely disposedwith respect to one of the bank conductors and a flexible resilientshank portion which is fixedly mounted at a point remote from its wiperend. Each set of wipers forms a part of one of the multi-contact relays,which relays further comprise means for simultaneously flexing the shankportions of the associated wipers to move the respective wiper endsthereof into engagement with their respective oppositely disposed bankconductors. More specifically, a bar of insulating material isassociated with each wiper set to engage the wipers of the associatedset at points adjacent the respective wiper ends thereof and a togglemechanism, comprising four arms, one of which includes the armaturepiece for an operating magnet, is provided for translating the bar,thereby, to ilex the shank portions of the associated wipers and to movethe respective wiper ends thereof into engagement with their respectiveoppositely disposed bank conductors. In order to minimize the spacerequirements of a switching unit of any given size, alternate ones ofthe multi-contact relays are disposed on opposite sides of the planeformed by the bank conductors, whereby the length of these conductors isutilized to the fullest extent.

The novel features believed to be characteristic of the invention areset forth with particularity in the appended claims. The invention, bothas to its organization and method of operation, together with furtherobjects and advantages thereof, will best be understood by reference tothe specification taken in connection with the accompanying drawings inwhich Figure 1 is a front view partially in section, illustrating oneframe of a switching unit constructed and arranged in accordance withthe present invention; Fig. 2 is a cross-sectional plan view of theapparatus illustrated in Fig. 1; Fig. 3 is a side view partially insection, illustrating the mode of mounting the relays with respect tothe bank conductor field; and Figs. 4 and 5 are detail viewsillustrating the construction of one of the wipers.

Referring now to Figs. 1, 2 and 8 of the drawings, there is illustratedone frame or section of the improved switching apparatus as comprising aplurality of substantially parallel, bare bank conductors Hi, allpositioned in substantially the same vertical plane, a plurality ofwipers arranged in sets, three of which are indicated generally at I2, I3 and i4, and means comprising a plurality of wiper switching mechanismsor relay structures l5, l6, l1, 18, etc, individually associated withthe wiper sets for actuating the wipers of the respective associ-.

ated sets. The bank conductors ID are arranged in evenly spaced apartrelation, and are supported on insulating members I 3, 23, etc. whichextend between and are secured to oppositely disposed channel-shapedframe members 2| and 22. More particularly, the conductor field ispreferably formed by slotting the insulating members i9, 20, etc. atcorrectly spaced intervals, following which the conductors are forcedinto the slots so that the sides of each slot tightly grip theaccommodated conductor. In order to complete the assembly, eachinsulating member has overlying its slotted surface a second insulatingmember which is held in position by a U-shaped clamping bar. Thus, thebank conductors ID are clamped between the insulating member I9 and acooperating insulating member 23 by means comprising screws 24 and 25which extend, respectively, through openings provided in the respectiveside portions of the oppositely disposed frame members 2i and 22,through openings drilled in the respective ends of the members I9 and23, and are threaded into tapped drill holes appropriately disposedalong a channel-shaped clamping member 25 which is coextensive with theinsulating member 23. Each of the other supporting assemblies isidentical with that just described.

As best shown in Figs. 4 and 5, each of the wipers is provided with awiper end 21, a flexible resilient shank portion 28, and a terminal end29. These wipers are preferably stamped from flexible resilientmaterial, such for example, as brass or bronze. The wiper end of eachwiper is formed by bending over the two halves of a spiit enlargedportion of the stamping so that a slot 9 is provided which is ofslightly less width than the diameter of the bank conductors. As thusconstructed, the internal faces of the bent over portions engageopposite sides of the associated bank conductor to form a two pointcontact therewith when the shank portion of the wiper is flexed to movethe wiper end into engagement with its associated bank conductor.

The mounting assemblies for the wipers of the various wiper sets are soarranged that each wiper is insulated from each of the other wipers.Since the respective assemblies for the various sets are identical, onlythat for mounting the wipers of the set l2 need be considered in detail.In brief, this assembly comprises a pair of flat insulating strips 30and 3| between which the shank portions of the wipers are clamped atpoints remote from the respective wiper ends of the wipers. The strips30 and 3i are clamped together with the shank portions of the wiperstherebetween by means comprising a U-shaped member 32, a frame member33, and stud screws 34 extending through openings in the members 32, 30and 3| and threaded into tapped drill holes provided in the frame member33. This frame member is mounted on the end frame members 2| and 22, bytwo bolts 35 and 35 extending through openings drilled in the sideportions of the oppositely disposed end frame members 2| and 22.

Due to the structure identity between the wiper actuating mechanisms l5,l6, l1, l3, etc., only that indicated generally at I need be consideredin detail. This mechanism, namely the mechanism I5, is mounted upon abracket comprising outwardly bent portions or bracket pieces 31 and 38formed integral with and extending horizontally from the frame member33. In brief, the mechanism comprises an operating magnet 39 supportedbetween end brackets 40 and 4i secured to the bracket pieces 31 and 33by screws 42 and 43, and an armature piece 44 forming one arm of a pairof toggle linkages for actuating the wipers of the set l2. These togglelinkages are located at the respective ends of the magnet 39, that atthe right end of the magnet as shown in Fig. 3 comprising, in additionto the armature piece 44, three additional arms 43, 43 and 41, thelast-mentioned of which is fixedly mounted on the bracket portion 31 ofthe frame member 33 by means of screws 43. The toggle linkage isinterconnected by suitable pivot studs 49, 50, SI and 52, the twolast-mentioned studs forming the respective pivot points for the arm 44and the armature piece 44. Normally, the armature piece is restrained toengage two stop members 53 and 54, respectively mounted on the endbrackets 40 and 4| by screws 55 and 53, respectively, through theprovision of a coil spring 41 interconnecting the lower end of thearmature piece 44 and a finger extending from the toggle linkage arm 41.

Since the second toggle linkage, namely, that provided at the left endof the operating magnet 39, as shown in Fig. 1, is identical with thatjust described, no further discussion is deemed necessary to anunderstanding of the operation thereof.

In order to actuate the wipers making up the wiper set i2 by means ofthe two toggle linkages just described, there is provided a cross member53 interconnecting the two linkages and having mounted thereon, by meansof screws 53 and 69, a bar of insulating material which is suitablyslotted along its free edge to accommodate the bent over halves of thewiper ends of the respective wipers. Preferably, the wiper ends are ofsuch size that they are freely movable in the iespective accommodatingslots provided in the bar of insulating material 6|.

The magnet 39 is energized through circuit connections, not shown,interconnecting the two ends of its winding with the terminal connectors62 and 63, which are adapted to be connected to the control apparatusassociated with the mechanism ii. In this connection is should possiblybe mentioned that the frame member 33 including the bracketportion 31thereof is constructed of a non-magnetic material such as bronze orbrass, whereby the magnetic circuit of the operating magnet 39 is notshort-circuited. This magnetic circuit comprises, in addition to theusual core for the magnet, the end brackets 43 and 4! and the armaturepiece 44 extending therebetween, all of these elements being constructedof a material such, for example, as iron, having good magneticproperties.

As pointed out above, normally the two toggle linkages embodied in thewiper actuating mechanism II are maintained in their cocked positionsthrough the bias exerted on the armature piece 44 by the coil spring 31.When, however, the magnet 39 is energized, it attracts its associatedarmature piece 44, thereby to pivot this piece in a clockwise directionand to break the two toggle linkages. Due to this operation, the twopivot studs 43 and ii are moved toward each other and the pivoted stud50 is moved in a clockwise direction. As a result. the bar of insulatingmaterial 3| is translated to the right, thereby to flex the shankportions of the wipers embodied in the wiper set I2 and to move therespective wiper ends of these wipers into engagement with theirrespective oppositely disposed bank conductors. As a consequence, thelines terminating at the bank conductors it are connected by way of thewiper springs to the lines terminating at the terminal ends of thewipers. Following the deenergizaticn of the magnet 39, the togglelinkages are returned to normal through the bias exerted on the armaturepiece 44 by the coil spring 51 and the supplemental bias exerted on thetwo linkages due to the resiliency of the wiper springs embodied in thewiper set l2.

Assuming that the size of the bank conductor' fleld is such that tenthree-conductor lines are terminated thereat, this group of lines isselected upon energization of the magnet 39. In accordance withwell-understood telephone practice, further selection of a particularline in this group may be attained by terminating the terminal ends ofthe wipers in the set I 2 in the contact springs of a group of lineselecting relays arranged in conventional manner.

As pointed out in the introductory portion of the specification, thesize of a frame or section of a given line capacity is minimized bypositioning alternate sets of the wipers on opposite sides of the planeoccupied by the bank conductors. This arrangement is best illustrated inFig. 3 wherein the wiper set l3 and the actuating mechanism associatedtherewith are mounted on the right side of the vertical plane formed bythe conductors l0, and the sets l2 and H, together with the actuatingmechanisms l5 and I1 respectively associated therewith, are mounted onthe left side of this plane. By this arrangement, the active length ofthe bank conductors may be utilized to the greatest extent.

While there has been described what is at present considered to be thepreferred embodiment of the invention, it will be understood thatvarious modifications may be made in the structure thereof, and it iscontemplated in the appended claims to cover all such modifications asfall within the true spirit and scope of the invention.

I claim:

1, Switching apparatus comprising, in combination, a plurality ofsubstantially parallel spaced bank conductors all positioned insubstantially the same plane, a set of wipers positioned on a lineextending transversely with respect to said conductors, each of saidwipers including a wiper end oppositely disposed with respect to one ofsaid bank conductors and a flexible resilient shank portion, meansfixedly mounting the shank portions of said wipers at points remote fromtheir respective wiper ends, an operating magnet, an armature piece forsaid magnet, and means including a toggle mechanism controlled by saidarmature piece for simultaneously flexing the shank portions of saidwipers to move the respective wiper ends thereof into engagement withtheir respective oppositely disposed bank conductors.

2. Switching apparatus comprising, in combination, a plurality ofsubstantially parallel spaced bank conductors all positioned insubstantially the same plane, a set of wipers positioned on a lineextending transversely with respect to said conductors, each of saidwipers including a wiper end oppositely disposed with respect to one ofsaid bank conductors and a flexible resilient shank portion, meansflxedly mounting the shank portions of said wipers at points remote fromtheir respective wiper ends, an operating magnet, an armature piece forsaid magnet, a bar of insulating material associated with said wipers,said bar engaging said wipers at points adjacent the respective wiperends thereof, and means including a toggle mechanism controlled by saidarmature piece for translating said bar thereby to flex the shankportions of said wipers and move the respective wiper ends thereof intoengagement with their respective oppositely disposed bank conductors.

3. Switching apparatus comprising, in combination, a plurality ofsubstantially parallel spaced bank conductors all positioned insubstantially the same plane, a set of wipers positioned on a lineextending transversely with respect to said conductors, each of saidwipers including a wiper end oppositely disposed with respect to one ofsaid bank conductors and a flexible resilient shank portion, meansfixedly mounting the shank portions of said wipers at points remote fromtheir respective wiper ends, an operating magnet, an armature piece forsaid magnet, a toggle mechanism including four arms one of whichcomprises said armature piece, and means including said toggle mechanismfor simultaneously flexing the shank portion of said wipers to move therespective wiper ends thereof into engagement with their respectiveoppositely disposed bank conductors.

4. Switching apparatus comprising, in combination, a plurality ofsubstantially parallel spaced bank conductors all positioned insubstantially the same plane, a set of wipers positioned on a lineextending transversely with respect to said conductors, each of saidwipers including a wiper end oppositely disposed with respect to one ofsaid bank conductors and a flexible resilient shank portion, meansfixedly mounting the shank portions of said wipers at points remote fromtheir respective wiper ends, an operating magnet, an armature piece forsaid magnet, a bar of insulating material associated with said wipers,said bar engaging said wipers at points adjacent the respective wiperends thereof, a toggle mechanism including four arms one of whichcomprises said armature piece, and means including said toggle mechanismfor translating said bar, thereby to flex the shank portions of saidwipers and move the respective wiper ends thereof into engagement withtheir respective oppositely disposed bank conductors.

HERBERT F. OBERGF'ELL.

